I had to use this because just adding startpage.com as the default search engine in Firefox for Android didn't work correctly; when selecting text and then selecting "StartPage.com Search" option only opened a blank startpage without the query. Using this add-on, I was able to add https://www.startpage.com/search/?q=%s and now searching for selected text opens a startpage with the query!

Awesome addon. Works perfectly :)

Excellent! My only problem with it is that the added search engines don't get synced by Firefox, so you have to manually add them again if you uninstall and reinstall the browser.

Very useful. Awesome.

Da pra add quantos mecanismos de pesquisa quiser aos padrões do firefox (q já deveria deixar add por padrão)

I'm very happy with this addon. It works perfectly. I'm no longer having any issues at all (I had an issue using an .ico file that I custom specified, but that's no longer an issue). Thank you very much to the developer for creating this! I'm very glad to be able to search my favorite image searches, dictionaries, book searches, etc., right from the address bar. It really helps to save time. Great work! :)

Something to be ware of (as noted when using the addon): it uploads your custom url to file.io due to a technical limitation in Firefox...